Electronic cassette type of radiation detection apparatus

ABSTRACT

An electronic cassette type of radiation detection apparatus having a sensor array including a plurality of sensors for detecting incident radiation has a connecting portion to which detachable additional function modules are connected. A selection unit is provided for changing a radiographing mode from a still image radiographing mode and a moving image radiographing mode into a selectable state in response to a connection of at least one of the additional function modules changes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a radiation detection apparatus, and inparticular, to a mobile electronic-cassette radiation detectionapparatus.

2. Description of the Related Art

An X-ray image has been digitized in a hospital in recent years. A flattype of digital X-ray radiographing apparatus (hereinafter referred toas flat panel detector (FPD)) has been used instead of film. In additionto a stationary type of FPD, the FPDs include an electronic cassettetype which is mobile and easier to handle than the stationary type, asdescribed in Japanese Patent Application Laid-Open Nos. 2003-248060 and2005-013310.

There has been a demand for a lighter FPD with desired functions.

SUMMARY OF THE INVENTION

A conventional mobile electronic cassette type of radiation detectionapparatus, however, is only capable of photographing a still image. Acassette type of radiation detection apparatus has been desired which iscapable of photographing a moving image.

The present invention has its purpose to provide a mobile electroniccassette type of radiation detection apparatus which weighs little, hasfunctions which can be selected at discretion and is adapted to movingimage photographing.

To achieve the above purposes, an electronic cassette type of radiationdetection apparatus according to the present invention has a sensorarray including a plurality of sensors for detecting incident radiationand a connection portion to which a detachable additional functionmodule is connected, wherein a selection unit is provided for changing aradiographing mode from a still image radiographing mode and a movingimage radiographing mode into a selectable state in response toconnection to at least one additional function module.

The present invention provides an electronic cassette type of radiationdetection apparatus adapted to moving image photographing in which auser can select necessary functions at discretion.

Detaching the additional function modules from the electronic cassettetype of radiation detection apparatus makes the apparatus lighter,providing an electronic cassette type of radiation detection apparatuswhich is easier to carry and handle.

Other features and advantages of the present invention will be apparentfrom the following description taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1 is a cross section of an X-ray detecting apparatus in the firstembodiment of the present invention.

FIG. 2 is a side view of the X-ray detecting apparatus in the firstembodiment of the present invention.

FIG. 3 is a cross section of an X-ray detecting apparatus in the secondembodiment of the present invention.

FIG. 4 is a side view of the X-ray detecting apparatus in the thirdembodiment of the present invention.

FIG. 5 is a block diagram showing an example of a structure of X-rayradiation detection apparatus according to a first embodiment of thepresent invention.

FIG. 6 is a flow chart showing an operation of X-ray detection apparatusaccording to the first embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

An exemplary embodiment for carrying out the present invention isdescribed in detail below with reference to the drawings.

The embodiments of the electronic cassette type of radiation detectionapparatus according to the present invention are described below. In thepresent specification, the electronic cassette type refers to a mobileradiation detection apparatus for radiography. Radiation includesX-rays, alpha rays and gamma rays. In the following embodiments, inparticular, the electronic cassette type of X-ray detecting apparatus isdescribed, but this does not limit the present invention.

First Embodiment

The first embodiment of the electronic cassette type of X-ray detectingapparatus (electronic cassette) according to the present invention isdescribed below.

FIG. 1 is a cross section illustrating the structure of the electroniccassette in the present embodiment, viewed from the X-ray incident side.As illustrated in FIG. 1, a base plate 3 to which a sensor panel 2 isfixed is fastened to a casing 15. The sensor panel 2 is connected to aflexible printed circuit 4. The flexible printed circuit 4 is connectedto a driving circuit 5 or a reading circuit 6 arranged on the sideopposite to the sensor panel 2 of the base plate 3. The reading circuit6 is connected to a memory 8 being a storage device by a wiring (notshown). An analog signal read out from the sensor panel 2 is convertedto a digital signal by the reading circuit 6 and stored into the memory8. A control circuit 7 for operating the driving circuit 5, readingcircuit 6 and memory 8 is connected thereto by a wiring (not shown). Thecontrol circuit 7 is capable of synchronizing radiation exposure withthe operation of the driving circuit 5 and the reading circuit 6. Theelectronic cassette has a connecting terminal 9 being a connectingportion for connecting the electronic cassette 1 to an additionalfunction module 21. The additional function module 21 is connected toone of the driving circuit 5 and the reading circuit 6 through aconnection wiring 10. A battery (not shown) is disposed inside theelectronic cassette 1, permitting the electronic cassette 1 to beoperated without a cable. It is to be understood that the electroniccassette 1 may be operated with a cable connected, without disposing abattery in the casing. This is the basic configuration of the electroniccassette 1 in the first embodiment which is easy to carry and handle andcapable only of radiographing a still image. The connection of theadditional function modules 21 to the electronic cassette 1 adds amoving-image radiographing mode to the radiographing mode of theelectronic cassette 1 in addition to a still-image photographing mode.That is, a radiographing mode is changed a still image radiographingmode and a moving image radiographing mode into a selectable state. Theaddition of the additional function modules 21 makes the performance ofthe electronic cassette 1 desirable for moving image radiographing. Inaddition, it is desirable that the connection of at least one of theadditional function modules changes a radiographing mode from a modewhere only a still image can be radiographed to a mode where a movingimage can be radiographed.

It is also suitable, to make it easy to use the electronic cassette 1,that the electronic cassette 1 automatically changes in theradiographing mode depending upon whether or not the additional functionmodules 21 are connected to the basic configuration, as described below.For the automatic change of the radiographing mode, in the basicconfiguration, only a still image can be radiographed. Connecting atleast one of the additional function modules 21 changes theradiographing mode from the still-image radiographing mode to themoving-image radiographing mode. For this reason, detaching all theadditional function modules 21 from the electronic cassette 1automatically changes the radiographing mode from the moving-imageradiographing mode to the still-image radiographing mode. A controlcircuit operates as a selection unit for changing a radiographing modefrom a still image radiographing mode and a moving image radiographingmode into a selectable state.

In X-ray radiographing by using the electronic cassette 1 with the basicconfiguration, the electronic cassette 1 is connected to an externalcomputer to confirm images and transfers signals stored in the memory 8thereto. Only the memory 8 can be made detachable to be connected to anexternal computer. Signals are therefore processed in the externalcomputer and images are displayed on an external display.

The additional function modules 21 can be additionally connected to theelectronic cassette 1 with the basic configuration. The additionalfunction modules 21 include, for example, a storage device, imageprocessing circuit, display, wireless communication circuit, lightsource, cooling element, heat radiator plate and battery. At least oneof these additional function modules 21 is properly combined to beconnected to the electronic cassette 1, allowing radiographing a movingimage and extending the time period for the moving image radiographing.Thus, when a moving image is not radiographed, the electronic cassette 1can be reduced in weight, and when the additional function modules 21are connected, a moving image can be radiographed. FIG. 1 illustrates aconfiguration in which eight additional function modules 21 areconnected. The figure illustrates four out of eight additional functionmodules 21. In the present embodiment, a partitioning wall 14 isarranged between the areas where the sensor panel 2 and the additionalfunction modules 21 are disposed. The partitioning wall 14 can preventdust and moisture from entering the sensor panel 2 from the outside,with improved reliability of the electronic cassette 1. Examples of theadditional function modules connected to the electronic cassette 1 aredescribed below.

The connection of the storage device to the electronic cassette 1enables increasing capacity for storing signals. For example, a memoryor hard disk can be used. The connection of the storage device to theelectronic cassette 1 with the basic configuration enables to increasethe number of radiographed images and extend a radiographingtime-period. This is desirable particularly for the moving imageradiographing.

By connecting, to the electronic cassette, an additional circuit of areading circuit 6 provided with AD (analog to digital) converter forconverting an analog signal to a digital signal, the conversion can beaccelerated. And, by connecting, to the electronic cassette, anadditional circuit of a reading circuit 6 provided, a signal from thesensor panel 2 of a fundamental structure can be subjected to a parallelprocessing by the reading circuit 6 and a signal processing circuit. Incase that two or more AD converters are arranged in the reading circuitof the fundamental structure, if the signal processing circuit isprovided with the same number of AD converters as ones in the signalreading circuit 6, higher speed of the processing can be achieved.Accordingly, the configuration of the present embodiment is suitable forthe moving image radiographing in which high speed inputting of analogsignal is necessary. Moreover, when the reading circuit 6 is providedwith a low noise AD converter and a signal processing circuit of lowdriving speed most suitable for the still image radiographing and thesignal processing circuit is provided with AD converter and a signalprocessing circuit of high driving speed, a digital signal suitable forthe moving image can be derived.

The connection of the image processing circuit to the electroniccassette 1 enables to correct a signal transferred from the readingcircuit 6. For example, the image processing circuit performs a fixedpattern noise correction, defect correction and gain correction. It alsoproperly selects and performs the following processes; recognition ofX-ray irradiation field, gray scale transform adapted to imagediagnosis, reduction of grid stripes, frequency processing (edgeemphasis, emphasis of portions lower in contrast and sharpness),addition of signals. An image processing circuit processes the digitalsignal form the reading circuit 6 using FPGA (Field Programmable GateArray), or SOC (System On a Chip). This structure does not cause adelaying and therefore suitable for the moving image since the signalprocessing is performed within the electronic cassette. And, the imageprocessing circuit including the FPGA or SOC adapted to a necessaryimage processing function can be selected for being connected.Accordingly, since unnecessary image processing circuit is notconnected, power supplying to such unnecessary image processing circuitcan be saved. The power consumption can be reduced. For the still imageradiographing, real time monitoring is not always necessary.Accordingly, the fundamental structure thereof does not include theimage processing circuit. In case of such structure, the digital signalform the reading circuit 6 is directly outputted to an external.However, even in such case, the image processing circuit provided withFPGA and SOC having minimum function such as a fixed pattern noisecorrection or the like may be provided therein in the still imageradiographing. Because, such minimum function structure is in generalrelatively low power consumption one. If the image processing circuithas a function to output signals to the outside, the circuit can beconnected to the external display to display X-ray images. In suchstructure, since it is unnecessary to output the signal to the externalimage processing circuit, high speed moving image can be performed.

The connection of the display to the electronic cassette 1 permitsconfirming X-ray images in real time at a place of X-ray radiographing.If the electronic cassette 1 is configured so as to house the displaytherein, a portion of the casing corresponding to the additionalfunction modules 21 is made of transparent material. Data reduced by afunction of adding pixel of the image processing circuit is sent to thedisplay to be displayed thereon in real time. An opaque partitioningwall may be provided between the sensor panel 2 and the additionalfunction modules 21 to prevent picture quality from degrading byirradiating the sensor panel 2 with light of the display. The connectionof the display to the electronic cassette 1 allows radiographing in realtime.

The connection of the wireless communication circuit to the electroniccassette 1 allows transmitting X-ray radiographed signals to an externalcomputer. The external computer performs a predetermined process andimages are displayed on an external display. If the foregoing imageprocessing circuit is connected to the electronic cassette 1 at thatpoint, signals can be directly transmitted to the external display to bedisplayed thereon. This makes it easier to carry the cassette and toconfirm images. If an object of radiography has an IC tag with anindividual identification signal, the X-ray radiographed signal can beprovided with an individual identification data, which allows clearlyidentifying the object with the image. Particularly in the moving imageradiographing, the connection of the wireless communication circuit tothe electronic cassette 1 further enables long-time X-ray radiographingirrespective of the capacity of the storage device.

The connection of the light source to the electronic cassette 1 allowsthe optical reset of the sensor panel 2. In this case, since the sensorpanel 2 is irradiated with light, a light guide plate is arranged inadvance on the side opposite to the X-ray incident side of the sensorpanel 2. The light source is connected to irradiate the panel withlight, further adding an optical reset function to restrain change inpicture quality due to changing of sensor characteristics with time.

The connection of the cooling element to the electronic cassette 1 cansuppress a rise in temperature inside the electronic cassette 1 due toheat generated during the operation of one of the driving circuit 5 andthe reading circuit 6. This suppresses change in characteristics due tochange in temperature of the sensor panel 2. Accordingly, change inpicture quality can be suppressed. The connection of the cooling elementto the electronic cassette 1 in the moving image radiographing, inparticular, can provide an image with less degrading with time if acontinuous X-ray radiographing is performed for a long time. For thisreason, a time period is extended during which images can becontinuously radiographed with the power supply turned on, irrespectiveof the radiographing mode such as still image radiographing or movingimage radiographing.

The connection of the heat radiator plate to the electronic cassette 1produces the same effect as that of the cooling element.

The connection of the battery to the electronic cassette 1 allowsextending the operating time of the electronic cassette 1. If otheradditional function modules mentioned above are connected, consumptionpower is increased, so that it is desirable to connect the battery tothe electronic cassette at the same time. The connection of the coolingelement or the heat radiator plate and the battery as the additionalfunction module forms the minimum configuration which is best suited forlight weight and long-time moving image radiographing. This is becausethe configuration can maintain the optimum operating temperature in thedevice for a long time. And, the electronic cassette 1 achieves highspeed moving image radiographing by further adding thereto a readingcircuit. In case of adding the reading circuit, though the powerconsumption and heat generation increase, since the cooling element orheat radiation plate and battery are already connected thereto, longtime operation of the apparatus and maintaining a suitable operationtemperature are achieved.

The aforementioned additional function modules can be provided with acontrol circuit. This enables bilateral communication with the controlcircuit 7 in the electronic cassette 1 and distributed processing,increasing a processing speed.

The electronic cassette 1 can be provided with a recognition unit forrecognizing the connection of the above additional function modules andkinds thereof. For example, an optical sensor, magnetic sensor andswitch are used as the recognition unit.

FIG. 2 is a side view illustrating the structure of the electroniccassette type of X-ray detecting apparatus in the present embodiment. Asillustrated in FIG. 2, a lid 16 of an insertion portion for theadditional function module 21 is fixed to the casing 15 by a lockmechanism 17. By means of such configuration, the additional functionmodule 21 can be readily held, to maintain a condition within theapparatus.

FIG. 5 is a block diagram showing an example of a structure of X-rayradiation detection apparatus according to a first embodiment of thepresent invention.

In the electronic cassette 1, the fundamental structure 20 and theadditional function module 21 are connected through a connectingterminal 9.

The fundamental structure 20 comprises a sensor pane 12, a first readingcircuit 31, a first image processing circuit 33, a drive circuit 5, acontrol circuit 7, a first memory device 37, a first battery 35 and aconnecting terminal 9. And, an additional function module 21 connectedto the fundamental structure 20 comprises a second reading circuit 32, asecond image processing circuit 34, a second battery 36, a second memorydevice 38, a display 41, a wireless communication circuit 42, a coolingelement 43 and a thermal radiator plate 44. Needless to say, it is notalways necessary to connect all of the elements of the additionalfunction module 21 when the electronic cassette suitable for the movingimage radiographing is to be provided.

In case of the X-ray radiographing using the electronic cassette 1,firstly, a signal (analog) converted from X-ray is read out through thesensor panel 2, the drive circuit 5, the first reading circuit 31 andthe control circuit 7. The first reading circuit 31 converts the analogsignal transferred from the sensor panel 2 into a digital signal. Thedigital signal is subjected to an image processing meeting the minimumrequirements as the occasion demands. And, the digital signal is storedin the first memory. A power necessary for an operation of thefundamental structure 20 is supplied form the first battery 35.

Wherein, the second reading circuit 32 conducts a processing of parallelconversion of the analog signal divisionally inputted from the firstreading circuit 31 into the digital signal. For the signal conversion,the power consumption and heat generation quantity are mage larger.

The second image processing circuit conducts a high level imageprocessing rather than the first image processing circuit 33.Accordingly, the power consumption and heat generation quantity are magefurther larger.

The cooling element 43 cools a thermal generation portion such as thefirst and second image processing circuits 31 and 32. The thermalradiator plate 44 performs a heat radiation efficiently from an insideof the electronic cassette 1. Accordingly, even in case of connecting amodule of a larger heat generation such as the signal processing circuitand the image processing circuit, a temperature suitable for theapparatus operation can be maintained.

The signal transfer between the first and second reading circuits 31 and32 is not necessarily always through the control circuit 7. The signaltransfer between the first and second image processing circuits 33 and34 is not necessarily always through the control circuit 7. And, thesignal transfer between the first and second memory circuits 33 and 34is not necessarily always through the control circuit 7. With regard tothe other additional modules such as the display and the wirelesscommunication circuit, similarly, the communication to the circuits ofthe fundamental circuit 20 may be performed not through the controlcircuit 7.

FIG. 6 is a flow chart showing an operation of X-ray detection apparatusaccording to the first embodiment of the present invention.

To the fundamental structure 20, the additional function module 21 isconnected (step 51). The control circuit 7 detects the connection of theadditional function module 21, and a kind of the additional functionmodule 21 (step 52). The control circuit 7 operates as selection unitfor changing a radiographing mode from a still image radiographing modeand a moving image radiographing mode into a selectable state. In thisembodiment, the mode is set such that the moving image radiographing canbe performed. And, a selection switch of the radiographing mode isturned on (step 53). The step 53 is executed only in a case that theradiographing mode change is necessary. That is, in case that theradiographing mode to be executed is the still image radiographing mode,without executing the step 53, the operation process proceeds to step54. In case that the radiographing mode is to be changed automaticallyor manually from the still image radiographing mode, the operationprocess proceeds to step 55. At the step 55, speed 6 fps (frame/sec.) or30 fps (frame/sec.) of the moving image radiographing mode is selectedfor providing a desirable moving image (step 56 or 57).

Second Embodiment

FIG. 3 illustrates the electronic cassette in the present embodiment.

The point different from the first embodiment is that the additionalfunction module 21 is connected to the outside of the electroniccassette 1 in the present embodiment.

This configuration can realize a lighter and smaller electronic cassette1 if the additional function modules 21 are not connected thereto.

The additional function modules 21 are housed in the module casing 22.This configuration protects the additional function modules 21 againstshock and makes it easy to handle the additional function modules 21.Alternatively, the additional function modules 21 may be individuallyconnected to the electronic cassette 1.

Third Embodiment

FIG. 4 illustrates the electronic cassette in the present embodiment.

The point different from the second embodiment is that the additionalfunction modules 21 are connected to the side opposite to the X-rayincident side outside of the electronic cassette 1 in the presentembodiment.

As is the case with the second embodiment, this configuration can alsorealize a lighter and smaller electronic cassette 1 if the additionalfunction modules 21 are not connected thereto. In addition, even if theadditional function modules 21 are connected, the surface area on theX-ray incident side of the electronic cassette 1 can be kept small,which makes it easy to handle.

The additional function modules 21 are housed in the module casing 22.This configuration protects the additional function modules 21 againstshock and makes it easy to handle the additional function modules 21.Furthermore, a cooling element larger in surface area can be connectedas the additional function module 21, further improving a coolingefficiency. Still furthermore, a larger-screen display can be connectedas the additional function module 21, increasing accuracy in confirmingimages.

Alternatively, the additional function modules 21 may be individuallyconnected to the electronic cassette 1.

In the above first to third embodiments, the modes are described inwhich the electronic cassette 1 with the basic configuration isconnected to the additional function modules 21. In the presentinvention, additional function modules which are mobile and capable ofadding other new functions can be connected to the electronic cassette1, other than the above additional function modules. It is desirablethat the electronic cassette 1 and the additional function modules 21have a function such as the lock mechanism 17 illustrated in FIG. 2 toprevent the additional function modules 21 to hold on when connected.

In the above second and third embodiments, the modes are described inwhich the additional function modules 21 are connected to the outside ofthe electronic cassette 1, however, the electronic cassette 1 may behoused inside the module casing 22, for example, irrespective of theabove modes.

With the sensor panel 2, a plurality of sensors capable of detectingradiation is arranged in two dimensions to form a sensor array. A directconversion type of converting element such as, for example, a-Se fordirectly converting radiation into electric charge is used as thesensor. A photoelectric conversion element, for example, for indirectlyconverting radiation into electric charge is used as the sensor. In thephotoelectric conversion element, a scintillator disposed on theradiation incident side of the photoelectric conversion element convertsincident radiation into visible light and the photoelectric conversionelement converts the visible light emitted from the scintillator intoelectric charge. Switching elements such as, for example, TFTs areconnected to a plurality of sensors in the sensor array. Electriccharges converted from radiation incident on the sensors are transferredby driving TFTs connected to the sensors with a driving circuit. Inparticular, thallium with columnar crystal structure formed byevaporation or sodium doped CsI is used in the scintillator. As anotherexample of a scintillator, a phosphor layer is used which is formed bycoating and hardening phosphor powder with granular crystallinestructure such as Gd₂O₂S on binder resin such as polyester.

As many apparently widely different embodiments of the present inventioncan be made without departing from the spirit and scope thereof, it isto be understood that the invention is not limited to the specificembodiments thereof except as defined in the claims.

This application claims the benefit of Japanese Patent Application Nos.2006-232349, filed Aug. 29, 2006, and 2007-152707, filed Jun. 8, 2007,which are hereby incorporated by reference herein in their entirety.

1. An electronic cassette type of radiation detection apparatuscomprising: a sensor array including a plurality of sensors fordetecting incident radiation; and a connecting portion for connectingthe electronic cassette type of radiation detection apparatus to adetachable additional function module; wherein a selection unit isprovided for changing a radiographing mode from a still imageradiographing mode and a moving image radiographing mode into aselectable state in response to connection of the electronic cassettetype of radiation detection apparatus to at least one additionalfunction modules.
 2. The electronic cassette type of radiation detectionapparatus according to claim 1, wherein the radiographing mode ischanged from the still image radiographing mode to the moving imageradiographing mode.
 3. The electronic cassette type of radiationdetection apparatus according to claim 1, wherein the additionalfunction module is a storage device.
 4. The electronic cassette type ofradiation detection apparatus according to claim 1, wherein theadditional function module is a signal processing circuit.
 5. Theelectronic cassette type of radiation detection apparatus according toclaim 1, wherein the additional function module is an image processingcircuit.
 6. The electronic cassette type of radiation detectionapparatus according to claim 1, wherein the additional function moduleis a display.
 7. The electronic cassette type of radiation detectionapparatus according to claim 1, wherein the additional function moduleis a wireless communication circuit.
 8. The electronic cassette type ofradiation detection apparatus according to claim 1, wherein theadditional function module is a light source.
 9. The electronic cassettetype of radiation detection apparatus according to claim 1, wherein theadditional function module is a cooling element or heat radiator plate.10. The electronic cassette type of radiation detection apparatusaccording to claim 1, wherein the additional function module is abattery.
 11. An electronic cassette type of radiation detectionapparatus comprising: a sensor array including a plurality of sensorsfor detecting incident radiation; and a connecting portion forconnecting the electronic cassette type of radiation detection apparatusto a detachable additional function module; wherein a selection unit isprovided for changing a radiographing mode from a still imageradiographing mode and a moving image radiographing mode into aselectable state in response to connection of the additional functionmodules to at least a cooling element or a heat radiator plate and abattery as the additional function module.
 12. The electronic cassettetype of radiation detection apparatus according to claim 1, wherein theadditional function module is housed in a casing.
 13. The electroniccassette type of radiation detection apparatus according to claim 1,wherein the electronic cassette type of radiation detection apparatus isconnected to the additional function modules through the connectingportion.